1. Field of the Invention
The present invention relates to an image reading system and method, particularly to a system and method usable irrespective of order of radiographing and input of reading conditions of radiographed image data.
2. Description of Related Art
An image obtained by using radiation, such as X-ray or the like, has been known widely as a medical image for diagnosing diseases. For example, so-called X-ray photograph by which development is performed by irradiating the X-ray transmitted through a subject to a phosphor layer (phosphor screen) and irradiating the visible light generated in the phosphor layer to a film, in which silver salts are used as the same as usual photograph, has been used in earlier technology.
However, recently, a method for taking out an image directly from a phosphor layer has been used instead of a film coated with silver salts. This method is a method for obtaining image signals explained as follows. That is, after the X-ray transmitted through a subject is absorbed into a phosphor, the phosphor layer is excited by light or heat and X-ray energy accumulated in the phosphor layer is emitted as a fluorescence light. Then, the fluorescence light is converted photoelectrically into image signals.
Concretely, for example, an X-ray image converting method in which a stimulating phosphor is used and visible rays or infrared rays are used as stimulating excitation lights is disclosed in the U.S. Pat. No. 3,859,527 and the Japanese Patent Laid-Open Publication No. 55-12144. In this method, a radiographic image converting plate in which a stimulating phosphor layer is formed on a supporting member is used. The X-ray transmitted through a subject is irradiated to this stimulating phosphor layer, and a latent image is formed by accumulating the X-ray energy corresponding to the quantity of X-ray transmitted through each body part of the subject. Thereafter, the stimulating phosphor layer is scanned by a stimulating excitation light, such as laser beam having a predetermined wavelength or the like, and the accumulated X-ray energy is emitted as a stimulating light. Then, the stimulating light is converted photoelectrically into electric signals by using a photoelectric transducer, such as photomultiplier or the like, and the electric signals are taken out.
The X-ray image radiographing utilizing the stimulating phosphor can be roughly classified into two types. One is a exclusive type that a radiographic image converting plate is fixed, and the other is a cassette type that a cassette containing a radiographic image converting plate in the inside thereof and capable of being carried is used. The X-ray image radiographing of the above-described cassette type will be explained with reference to FIG. 17.
As shown in FIG. 17, the X-ray image radiographing of the above-described cassette type is performed by a system including a cassette 110 capable of being carried, in which a radiographic image converting plate having a stimulating phosphor sheet 130 for accumulating X-ray energy is built, a reader 200 for reading an X-ray image from the cassette 110, and a controller 300 for controlling the reader 200 and performing display and input.
Then, a subject M is located between an X-ray source 140 and the cassette 110, and an X-ray is irradiated from the X-ray source 140. The stimulating phosphor sheet 130 in the cassette 110 accumulates a part of irradiated radiation energy. Then, when this cassette 110 is set in the reader 200, an excitation light is irradiated to the stimulating phosphor sheet 130 in order to read out the X-ray image information accumulated in the stimulating phosphor sheet 130 in the cassette 110, in the reader 200. Then, the stimulating light body which emits a light in accordance with the X-ray image information accumulated by the irradiated excitation light is converted photoelectrically, and A/D conversion is carried out. Thereafter, the reader 200 outputs it as digital image data.
Further, the controller 300 performs the control of reading of the reader 200, and also has a monitor for inputting the order information, such as patient information, body parts for radiographing and the like, and for confirming the read image. In order to deal with various workflows, there have been many cases such that the reader 200 and its exclusive controller 300 are installed in one or a set of the reader 200 and its exclusive controller 300 being connected separately by 1 to 1 are installed in an X-ray room.
However, high accuracy is required for these systems since they are used in medical diagnosis, so that the cost is extremely high. Therefore, it is noneconomic to install a reader 200 and controller 300 regardless of frequency of radiographing in a radiographing room, and furthermore, the installation space becomes large. Thereby, there are many cases that the reader 200 and controller 300 are installed only in the radiographing room of high frequency of radiographing. In such a constitution, in case that radiographing is performed in a radiographing room in which the above-described set is not installed, the cassette 110 is carried into the radiographing room at first, and after radiographing is performed, the cassette 110 is moved into the radiographing room in which a reader 200 is installed in order to read the radiographed X-ray image. Thereby, there is a possibility that the correspondence between the cassette 110 and the patient may become unclear when radiographing is performed to many patients among many radiologists.
Further, the time after going to the reader 200 from the radiographing room, setting the cassette 110 and confirming the image until returning to the radiographing room becomes long. Therefore, there is a problem such that the burden to patients becomes large since the radiographing time becomes long, or the like.
Then, in order to make the correspondence between the cassette 110 and the reading conditions of a radiographic image converting plate clear even though it is the case that radiographing of the X-ray image and reading take place in different places, a method for performing radiographing after registering the correspondence between the cassette 110 and the reading conditions of the radiographic image converting plate beforehand (hereinafter, the method for performing radiographing after registering the correspondence is called “pre-registration”) has been used. The procedure according to the pre-registration type will be explained in the following.
In this method, the order information, such as body parts for radiographing, sensitivity, resolution and the like, are inputted by the controller 300, input terminal or the like. At the same time, the ID information of an identification label for identifying the stimulating phosphor sheet 130 contained in the cassette 110 is read, and is registered in a database through a network as information by being made to correspond to the sensitivity, resolution. Then, radiographing is carried out to a patient by using the registered cassette 110. Thereafter, the cassette 110 is set in the reader 200, and the ID information of the stimulating phosphor sheet 130 is read by an identification label detector which is connected to or built in the reader 200. The reader 200 refers to the database by making the read ID information search key, and obtains the address of the controller 300 in which the sensitivity, resolution and the reading conditions of the radiographic image converting plate are registered, from the database. Then, the X-ray image information accumulated in the stimulating phosphor sheet 130 is read by using the sensitivity and resolution, and the reader 200 sends the ID information and the X-ray image information to the controller 300 of the obtained address. The controller 300 receives the ID information and the X-ray image information from the reader 200, and specifies the reading conditions of the radiographic image converting plate from the ID information. Then, the controller 300 determines the image processing method from the body parts for radiographing, performs the image processing, and displays the image.
According to the system using this method, it is possible to connect a plurality of readers 200 and controllers 300 in a network. Further, the installation space can be made small by installing only the controller 300 in each radiographing room in a hospital and by installing a plurality of readers 200 in a common space among the radiographing rooms.
The above-described system adopting the pre-registration is effective in a mode that many radiologists perform radiographing to many patients, such as in a large hospital or the like, since the installation space of the readers 200 and controllers 300 can be made small. However, in case that one or few radiologist performs radiographing in one radiographing room, such as in a clinic or the like, there is a problem that operation becomes complicated on the contrary since the correspondence between the reading conditions, such as sensitivity, resolution and the like, and the ID information of the cassette 110 has to be registered at every radiographing even though the correspondence between the cassette 110 and the patient is clear. Further, in case in a large hospital, there is a problem that quick procedure cannot be carried out since registration of a cassette 110 beforehand is required even though when radiographing must be performed immediately, such as in emergency or the like.
Then, the inventor suggests a registering method which can make the correspondence between a cassette 110 and the reading conditions of a radiographic image converting plate clear without performing the registration of the cassette 110 before radiographing (hereinafter, the type which the correspondence is registered after radiographing is called “post-registration”) in the earlier Japanese Patent Laid-Open Publication No. 11-289426. The outline of the technology in the above-described Publication will be explained.
In the post-registration type, the order information (sensitivity and resolution of reading conditions of a radiographic image converting plate, patient information, body parts for radiographing and the like) are inputted by a controller 300 or input terminal after radiographing is performed. Then, the sensitivity and resolution of the reading conditions of the radiographic image converting plate and the ID which shows that it is post-registration (ID for post-registration) are made to correspond, and are registered in a database through a network by taking the input order into consideration. Then, when the cassette 110 is inserted into the reader 200, the reader 200 refers to the database by using the ID information for post-registration, and obtains the address of the controller 300 in which the sensitivity, resolution and the reading conditions of the radiographic image converting plate are registered in accordance with the correspondence between the input order of the reading conditions of the radiographic image converting plate and the insertion order of the cassette 110. Thereafter, the X-ray image information accumulated in the stimulating phosphor sheet 130 in the cassette 110 is read by using this sensitivity and resolution, and the reader 200 sends the ID information and the read X-ray image information to the controller 300 of the obtained address. The controller 300 receives the ID information and the X-ray image information from the reader 200, and specifies the order information from the reception order. Then, the controller 300 determines the image processing method from the body parts for radiographing, performs the image processing, and displays the image.
In the post-registration type, it is not required to register the correspondence between the reading conditions of the radiographic image converting plate, such as sensitivity, resolution and the like, and the ID information of a cassette 110 before radiographing. Therefore, in case that one radiologist performs radiographing in one radiographing room, such as in a clinic or the like, the efficiency of operation can be improved. Further, since radiographing can be performed immediately in an emergency, quick procedure becomes possible.
Thus, in a hospital in which many readers 200 and controllers 300 are installed in different places, respectively, and many radiologists perform radiographing, or the like, radiographing of many patients can be performed effectively according to the pre-registration. On the other hand, in a clinic in which the number of installed readers 200 and controllers 300 is small and a few radiologists perform radiographing, or the like, radiographing can be performed quickly and effectively according to the post-registration. However, only one of registration types can be utilized. Therefore, for example, there is a problem such that quick radiographing cannot be performed in an emergency in a hospital, or that inconvenience may be caused when expanding the system by extending the readers 200 or controllers 300 in a clinic.